Spin Polarized Inelastic Neutron Scattering

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Spin Polarized Inelastic Neutron Scattering

• NIST Summer School on Neutron Spectroscopy

Seung-Hun Lee Peter Gehring Sungil Park
Alina Visinoiu Gokhan Caliskan Erick
Lawson Martin Sulic Tessema Guebre Xabiher Kapil
Gupta Jose Rodriguez Mike Lewis
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ZnCr2O4-Space Group-Fm3d
Edge-sharing octahedra
Magnetic frustration
H -J S Si . Sj
All exchange interactions can not be satisfied.
or
Magnetic Phase Transition in ZnCr2O4
QCW -390 K TN 12.5 K
Corner-sharing tetrahedra (B sites)
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SPINS
Increased data acquisition Rate over conventional
TAS By an order of magnitude.
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Exploring Statics
(H,K,L)(1,1,1)

• Q resolution0.02 Å-1
• Doubling of the unit cell

Intensity
(1/2,1/2,3/2)
(1/2,1/2,1)
Q(Å-1)
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Order Parameter
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Exploring Dynamics
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Inelastic Resonance Peak
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?-Correlation Length
T15KgtTN 0.6meVltElt1.4meV HWHM?0.45Å ?2.2Å
T1.5KltTN 4.2meVltElt1.4meV HWHM?0.36Å ?2.8Å
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Summary

• SPINS probes both the static crystal and magnetic
  state of the system.
• SPINS probes the dynamic behavior of the system.
• SPINS is a relatively fast spectroscopy
  technique.
• SPINS is ideal for studying specific regions in
  Q-? space.

• Acknowledgements
• NIST
• NSF
• NCNR